Executive functions (EFs) are general-purpose brain mechanisms that allow for self-regulated thought and behavior, and they are critical to intelligence and mental health. However, despite their importance, EFs are poorly understood. Our first goal is to better understand the cognition underlying EFs and EF deficits;we therefore propose a large-scale laboratory study that tests for individual differences in several elemental EF abilities (involving control of attention and memory) using multiple tasks that are tractable and theoretically grounded enough to suggest underlying brain mechanisms. Our second goal is to better understand how particular EF deficits contribute to daily-life functioning and development of mental-health disorders, such as schizophrenia. We address this in two ways. First, the laboratory EF study will also measure schizotypy-a multifaceted aspect of personality reflecting mild schizophrenic-like symptoms that heightens risk of later developing schizophrenic disorders. Second, an experience-sampling study of these same participants will question them at random intervals in their daily lives to assess cognitive and emotional experiences and to test whether the lab measures of EF and schizotypy predict particular mental and behavioral problems in everyday living. The specific aims of the proposed research are: 1) To assess the psychological structure of EF capabilities that reflect the control of working memory (maintaining and updating mental representations), the control of attention (sustaining and constraining conscious focus amid distraction), and the control of action (restraining habitual but inappropriate responses), and to assess their prediction of schizotypy in a large structural equation modeling study. 2) To illuminate the functional significance of EF and schizotypy in a large experience-sampling study that uses a daily-life "beeper" method to test how EF abilities measured in the laboratory moderate some of the cognitive and emotional problems experienced by schizotypic adults, such as confusion, distraction, paranoia, disturbing thoughts, social dysfunction, and communication difficulties. The proposed research is innovative in integrating the expertise of cognitive, social, and clinical psychologists and in combining laboratory, individual-differences, and ecological-sampling methods to clarify the nature of EFs, to determine the EF dimensions that predict schizotypy, and to evaluate the impact of EF and schizotypy differences on mental functioning as it unfolds in daily life. This will have a significant impact on our measurement and understanding of the brain's EFs and their contributions to serious psychopathology. PUBLIC HEALTH RELEVANCE: Executive functions-the brain mechanisms allowing for self-regulation of behavior, emotion, and thought- vary in effectiveness from person to person and are disrupted in many mental-health disorders, including AD/HD and schizophrenia. The proposed research will advance the basic science of executive functions as well as illuminate the role that individual differences in executive function play in schizotypy, a collection of personality characteristics that significantly predict risk for developing schizophrenia and a variety of daily-life impairments.